For more than six decades, chromic acid anodizing （CAA） has been the central process in the surface pre-treatment of aluminum for adhesively bonded aircraft structures. Unfortunately, this electrolyte contains hexav...For more than six decades, chromic acid anodizing （CAA） has been the central process in the surface pre-treatment of aluminum for adhesively bonded aircraft structures. Unfortunately, this electrolyte contains hexavalent chromium （Cr（VI））, a compound known for its toxicity and carcinogenic properties. To comply with the new strict international regulations, the Cr（VI）-era will soon have to come to an end. Anodizing aluminum in acid electrolytes produces a self-ordered porous oxide layer. Although different acids can be used to create this type of structure, the excellent adhesion and corrosion resistance that is currently achieved by the complete Cr（VI）-based process is not easily matched. This paper provides a critical overview and appraisal of proposed alternatives to CAA, including combinations of multiple anodizing steps, pre- and post anodizing treatments. The work is presented in terms of the modifications to the oxide properties, such as morphological features （e.g., pore size, barrier layer thickness） and surface chemistry, in order to evaluate the link between fundamental principles of adhesion and bond performance.展开更多
During the reign of Emperor Wu of Han Dynasty,the ethnic relations in China entered a new historical stage.Records of the Historian written during this period gives a basically factual account of the ethnic history in...During the reign of Emperor Wu of Han Dynasty,the ethnic relations in China entered a new historical stage.Records of the Historian written during this period gives a basically factual account of the ethnic history in China since ancient epochs.It is the first specialized work on ethnic history.The national consciousness that Sima Qian presents in this work is distinctively different from the Confucian tradition,which draws a strict line between Hua(华,China)and Yi(夷,the barbarians).His attention on the commonality of the cultural genes between the farming peoples of the Central-Plains and the nomadic hunting peoples of the borderlands,his recognition of the integrated impact that multiple ethnic groups have on the rise and development of Huaxia(华夏,Chinese)civilization,his respect for"differences among barbarians of the four directions"(四夷各异),and his approval of the“merits of Hu attire”(胡服之功)are all embodiment of his liberal views.To explore the formation and development of the cultural community of the Chinese nation and to understand and interpret this historical process of ethnic integration,we should attach great importance to the positive significance of Sima Qian's national consciousness.展开更多
As the amount of data continues to grow rapidly,the variety of data produced by applications is becoming more affluent than ever.Cloud computing is the best technology evolving today to provide multi-services for the ...As the amount of data continues to grow rapidly,the variety of data produced by applications is becoming more affluent than ever.Cloud computing is the best technology evolving today to provide multi-services for the mass and variety of data.The cloud computing features are capable of processing,managing,and storing all sorts of data.Although data is stored in many high-end nodes,either in the same data centers or across many data centers in cloud,performance issues are still inevitable.The cloud replication strategy is one of best solutions to address risk of performance degradation in the cloud environment.The real challenge here is developing the right data replication strategy with minimal data movement that guarantees efficient network usage,low fault tolerance,and minimal replication frequency.The key problem discussed in this research is inefficient network usage discovered during selecting a suitable data center to store replica copies induced by inadequate data center selection criteria.Hence,to mitigate the issue,we proposed Replication Strategy with a comprehensive Data Center Selection Method(RS-DCSM),which can determine the appropriate data center to place replicas by considering three key factors:Popularity,space availability,and centrality.The proposed RS-DCSM was simulated using CloudSim and the results proved that data movement between data centers is significantly reduced by 14%reduction in overall replication frequency and 20%decrement in network usage,which outperformed the current replication strategy,known as Dynamic Popularity aware Replication Strategy(DPRS)algorithm.展开更多
文摘For more than six decades, chromic acid anodizing （CAA） has been the central process in the surface pre-treatment of aluminum for adhesively bonded aircraft structures. Unfortunately, this electrolyte contains hexavalent chromium （Cr（VI））, a compound known for its toxicity and carcinogenic properties. To comply with the new strict international regulations, the Cr（VI）-era will soon have to come to an end. Anodizing aluminum in acid electrolytes produces a self-ordered porous oxide layer. Although different acids can be used to create this type of structure, the excellent adhesion and corrosion resistance that is currently achieved by the complete Cr（VI）-based process is not easily matched. This paper provides a critical overview and appraisal of proposed alternatives to CAA, including combinations of multiple anodizing steps, pre- and post anodizing treatments. The work is presented in terms of the modifications to the oxide properties, such as morphological features （e.g., pore size, barrier layer thickness） and surface chemistry, in order to evaluate the link between fundamental principles of adhesion and bond performance.
文摘During the reign of Emperor Wu of Han Dynasty,the ethnic relations in China entered a new historical stage.Records of the Historian written during this period gives a basically factual account of the ethnic history in China since ancient epochs.It is the first specialized work on ethnic history.The national consciousness that Sima Qian presents in this work is distinctively different from the Confucian tradition,which draws a strict line between Hua(华,China)and Yi(夷,the barbarians).His attention on the commonality of the cultural genes between the farming peoples of the Central-Plains and the nomadic hunting peoples of the borderlands,his recognition of the integrated impact that multiple ethnic groups have on the rise and development of Huaxia(华夏,Chinese)civilization,his respect for"differences among barbarians of the four directions"(四夷各异),and his approval of the“merits of Hu attire”(胡服之功)are all embodiment of his liberal views.To explore the formation and development of the cultural community of the Chinese nation and to understand and interpret this historical process of ethnic integration,we should attach great importance to the positive significance of Sima Qian's national consciousness.
基金supported by Universiti Putra Malaysia and the Ministry of Education(MOE).
文摘As the amount of data continues to grow rapidly,the variety of data produced by applications is becoming more affluent than ever.Cloud computing is the best technology evolving today to provide multi-services for the mass and variety of data.The cloud computing features are capable of processing,managing,and storing all sorts of data.Although data is stored in many high-end nodes,either in the same data centers or across many data centers in cloud,performance issues are still inevitable.The cloud replication strategy is one of best solutions to address risk of performance degradation in the cloud environment.The real challenge here is developing the right data replication strategy with minimal data movement that guarantees efficient network usage,low fault tolerance,and minimal replication frequency.The key problem discussed in this research is inefficient network usage discovered during selecting a suitable data center to store replica copies induced by inadequate data center selection criteria.Hence,to mitigate the issue,we proposed Replication Strategy with a comprehensive Data Center Selection Method(RS-DCSM),which can determine the appropriate data center to place replicas by considering three key factors:Popularity,space availability,and centrality.The proposed RS-DCSM was simulated using CloudSim and the results proved that data movement between data centers is significantly reduced by 14%reduction in overall replication frequency and 20%decrement in network usage,which outperformed the current replication strategy,known as Dynamic Popularity aware Replication Strategy(DPRS)algorithm.
